1. Field of the Invention
The present invention relates generally to electronic components. More particularly, the present invention relates to electronic components having an integral heat spreader.
2. Disclosure Information
Many types of electronic components produce excessive amounts of heat during operation which, if not transferred away from the component, might damage the component or retard its performance. One way of transferring heat away from such components is to attach an external heat sink to the component. This type of external heat sink might consist of a finned copper or aluminum block thermally attached to the top of the component. Another way of transferring excess heat away is to incorporate a heat sink into the component itself when it is manufactured; this type of integral heat sink is often referred to as a "heat spreader". FIGS. 1-4 illustrate this type of approach, wherein an integrated circuit (IC) 12 and its associated leadframe terminations 14 have been thermally attached to a heat spreader 16, over which an electrically non-conducting body 18 has been molded. The component 10 is attached to the substrate 20 by soldering the terminations 14 and heat spreader 16 to their respective solder pads 22. With this type of arrangement, heat from the IC 12 can be transferred by the integral heat spreader 16 to its associated solder pad 22. Heat may be further transferred away by a circuit trace to which the solder pad 22 is connected, and/or by thermal vias/heat pipes 26 disposed beneath and in thermal contact with the solder pad 22.
The type of component shown in FIGS. 1-4 is typically connected to a substrate by a process of (1) placing solder paste on the solder pads, (2) situating the component on the substrate such that its terminations and heat spreader rest atop their respective solder pads, thus forming an assembly, and (3) running the assembly through a conventional reflow oven which melts, reflows, and solidifies the solder paste so that solder joints form connecting the terminations and heat spreader to their associated solder pads. An alternative to using a reflow oven in step (3) above is to use laser soldering instead. In laser soldering, a beam of laser energy is directed at a solder deposition and/or a solder pad and/or a termination/heat spreader for an amount of time sufficient to transfer enough heat to the solder to melt it. The beam is then turned off or directed elsewhere, thus allowing the melted solder to solidify and form a solder joint connecting the termination/heat spreader with its solder pad.
Laser soldering works well for soldering terminations to their respective solder pads. However, it is difficult to direct a laser beam at a component's heat spreader if the spreader is situated completely underneath the component, or to transfer enough energy to the heat spreader if only a small portion of it protrudes out from underneath the component.
It would be desirable, therefore, to provide an electronic component which includes an integral heat spreader that is also capable of being easily laser soldered.